Improvement in speaking-telephones



G. MVPHELPS. Speaking-Telephone.

No. 209,289. Patented Oct. 22,1878.

UNITED STATES PATENT OFFIoE.

:G'EORGE M. PHELPS, OF BROOKLYN, NEW'YORK.

lMPROVEMENT lN SPEAKlNG-TELEPHONES.

Specification forming part of Letters Patent No- 209,289, dated October22, 1878 application. filed February 11, 1878.

To all whom it may concern:

Be it known that I, GEORGE lVLPHnLPs, of Brooklyn, in the county ofKings and State of New York, have invented certain new and usefulImprovements in Speaking or Articulating Telephones, which improvementsare 7 fully set forth in the following specification,

two or more corresponding magnetic cores enveloped in separate helices,connected with the same circuit, with a single mouth-piece orvocalizing-chamber; second, in mounting two magnetic cores, whencombined with separate diaphragms and coils and a single mouthpiece,upon opposite poles of the same permanent magnet; and, third, insubdividing a single continuous induction-plate into two or moreseparate and distinct areas of vibration, thus virtually forming two ormore separate diaphragms, each of which acts or is acted upon by aseparate magnetic core.

In the accompanying drawings, Figure 1 is a front view of aspeaking-telephone embodying my improvements. Fig. 2 is a verticaltransverse section of the same, and Fig. 3 is cross-section taken in theplane of the dotted line as w in Fig. 2.

The working parts of the instrument are inclosed within a hollow shellor case, A, which may be constructed of hard rubber, wood, or any othersuitable material, and should be provided with a suitable handle, 0. Arecess is formed within the case A, in which is placed apermanentmagnet, M, which forms a yoke to the soft-iron cores 0 e, whichare enveloped in helices E E of insulated wire, the whole arrangementbeing precisely similar to that of an ordinary horseshoe electro-magnetwith very short cores, except that the yoke M, in-

stead of being of soft iron, is of steel, and per- -manently magnetized,having its north and south poles at n and s, respectively. The cores 6 cof this magnet are thus rendered permanently magnetic by induction.

The poles of the cores 0 0 project into a shallow circular chamberformed within the case A, the depth of which is just equal to thecombined thickness of the inductive plate D and the dampers F G, betweenwhich the latter is firmly clamped when the case A isput together. I

The inductive plate D is shown in Fig. 2, in which figure one-half of it(to the right of the Vertical center line) has been removed in order toexhibit the parts beneath it. A section of the plateD is also shown inFig. 3. The dampers F and G, between which the plate D is clamped, arecomposed of thick soft paper, felt, or other equivalent substance, andare each in the form of a flat disk, as seen at F in Fig. 2, but with acircular opening opposite each pole of the magnet.

The effect of this mode of construction is that, when the plate D iscompressed between the dampers F and G, the only portions of it capableof being thrown into vibrations are those which are comprised within thearea of the circular openings in the dampers, and thus the plate D isvirtually converted into two circular vibrating diaphragms, d d1. (SeeFigs. 2 and 3.)

The mouth-piece B has two conical tubes or passages,'b 12 leading fromit, by which the sonorous vibrations entering the mouth-piece aresimultaneously concentrated upon the two vibrating diaphragrns (l and (1As the helices E and E are both placed in or connected with the sameelectric circuit, the ends of the wires being attached to thebinding-screws L L, for making connection with the line in the usualmanner, it will be obvious that the useful effect produced will benearly or quite double that of the ordinary arrangement, in which asingle diaphragm and helix are employed, and by which only one pole ofthe permanent magnet is utilized.

The distance between the poles of the magnet and the diaphragm may beadjusted by means of simple screws, acting to compress'the flat spring min a manner well understood.

It is obvious that the principle of construction which I have adoptedmay be carried still further, if found desirable. For example, thepermanent magnet M may be made in the form of a cross, having two northand two south poles, and provided with four helices and four diaphragms,all of which will act in concert, and will re-enforce the action of eachother, and even a greater number may be employed, if desirable, withoutdeparting in the least from the principle of my invention.

It is also obvious that separate plates might be employed for theseparate diaphragms instead of making use of a single plate subdividedinto distinct areas of vibration by compression between dampers, ashereinbefore described; but the use of a single plate produces equallygood results, and materially simplifies the construction and adjustmentof the instrument.

The helices or coils E E may be connected in series or in multiple arebetween the binding-screws L and L whichever may be advisable in anyparticular'instance.

I claim as my invention 1. Two or more magnetic cores whose en- Velopinghelices or coils are placed in the cirplates'or diaphragms and a singlemouth.

piece or vocalizing-chamber, substantially as specified.

3. A single induction-plate subdivided into two or more separate anddistinct areas of vibration, in combination with two or more magneticcores and. two or more helices or coils, substantially as specified.

In witness whereof I have hereunto set my hand this 5th. day ofFebruary, A. D. 1878.

GEO. M. PHELPS.

Witnesses G. A. HAMILTON, GERRITT SMITH.

